How do i get to 1800+ ??

[Shodokan]

For a 4 shaman team? You need a dedicated healer with good gear. Depending on the worth of the hilts on your server i'm sure you can nab someone off a 2k rated team for a day or so to get your rating. Be warned that "pro" pvp players can be very impatient for mistakes made.
I use to sell 2's ratings on my rogue in BC and season 6... if the person wasn't at least competent no amount of gold can make up for that and ultimately it will become a waste of time.

So you either need to find someone patient, or a healer who is so good that they can TELL you what to do. Since you are a multi-boxer it's highly unlikely of the latter.